Abstract

Most roe deer females produce twins and more rarely singletons and triplets. Some very rare reported cases of litters above three offspring refer to quadruplets which are, however, very much an exception in roe deer reproduction (only some tens of documented cases can be found in the scientific literature). In this paper, we present the first firm evidence that roe deer females are able to produce even five offspring. By examination of large sample set (n = 4690) of roe deer uteri and ovaries in two neighbouring countries in southern/central Europe (Italy and Slovenia), we found ten females that either carried or had potential to produce quadruplets, and in three does the (potential) litter size was even five. While one doe from Slovenia had five corpora lutea, two does from Tuscany, Italy, carried five foetuses. In both cases, all foetuses were normally and equally developed, indicating that none of them had predominant exposure to resorption/abortion. Six out of 13 females with exceptionally large potential litters (>3 offspring) had significantly higher body mass in comparison with mean body mass of all does harvested in the same hunting management district and in the same period, while five of them were significantly lighter. This indicates that some roe deer females can produce exceptionally large litters even when their phenotypic quality is not higher than the average in the population, and that such large litters are a stochastic episode rather than a reproductive performance of a very vital individual(s).

Notes

Acknowledgements

The Slovene part of the study was made by the financial support of the Slovenian Research Agency, aimed to educate Katarina Flajšman as a young researcher (contract no. 1000-12-0404), and which together with the Ministry of Agriculture, Forestry and Food financed the project V4-1627. We are grateful to the Arezzo Province for supplying data. We are indebted to M. Meacci for logistic support in collecting data for the Italian part of the study, and to Simona Diklič for improving the grammar of the manuscript. We would like to thank to all hunters who provided samples of roe deer reproductive organs which was a perquisite for performing the study.

Compliance with ethical standards

Conflicts of interest

The authors declare that they have no conflict of interest.

Ethical approval

All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All roe deer females used in the research were harvested during the regular hunting activity, i.e. prescribed by the national authorities of Slovenia and Italy within the yearly hunting management plans. Therefore, no animal was shot or killed by any other means for the purposes of the research in which we used reproductive organs of already dead animals.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Data availability statement

The datasets during and/or analysed during the current study are available from the corresponding author on reasonable request.